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Two very good counter points that should be considered. Those issues mean net cost analysis, Greenspeed probably will be more. Guess it depends how much heating cost savings there are in that big COP jump.

He'll probably not be putting in one much less two Greenspeeds, but without them in the cost/benefit analysis, the decision matrix is incomplete and biased. Poor or biased perspective leads to bad decisionmaking. If it were my audit I'd be modelling them to understand net cost.

But the home's lower level was cool even with supplies off and +60% RH,

My mother complained of icebox basement as well. We found that if she turns her fan to "On Medium" in April, then back to auto in July it seems to solve her icebox basement problem. I think she subsequently has gone to "On Low" the rest of the year, it keeps parts of the house from getting stale and dramatically cut dusting.

The idea was that by improving air circulation/mixing through the house during the period equipment otherwise seldom runs, and that the ground is coldest (pulling a lot of BTU from the basement that aren't being replaced), it evens temperatures throughout and you actually gain some cooling benefit to the rest of the house from the cold mass.

This assumes you have a low return in the basement, you want return pulling from the coldest location (hopefully Brian won't see this).

What is it about Greenspeed that is magic? Having tested one for a spring and summer, I was impressed with it's avoiding a few on/offs each day during medium cooling loads. But the home's lower level was cool even with supplies off and +60% RH, needing supplemental dehumidification to maintain <50%RH. Also at the very low speed cooling rates, the low air flow did not provide good circulation throughout the home. The system overcooled 3^F, which the occupants found annoying. Yet the entire house was +60%RH during low/no cooling load conditions. The system is 2X more expensive than a VS blow/medium seer a/c. After initial setup, maintaince and service will reqire the best techs and be pricey because of the cost of the components. Some of the components cost as much as simple a/cs.
If you want the best, regardless OK. But plan on including a whole house dehu to provide fresh air ventilation and <50%RH when the outdoor dew points are +55^F, with moisture from the occupants, and low/no cooling loads.
My past post show the data, or if you want specific data, request the condition. If pure magic is claimed get it in writing. It is pricey.
Regards TB

Originally Posted by Tommy knocker

Gotta agree with the Bear. I've been to 2 coarses on the Greenspeed and I'm not really impressed with it. I see extreme down the road costs and problems with PMs on it. You will either have to pay more for your PM or get half a$$ PM which will cost you big $$ to correct. Alot of thought and engineering went into and on paper it looks fantastic. Just don't see the potential minimal gain in efficiency worth the cost or the risk. It is a very complex unit with alot of stuff that frankly is over the heads of most residential techs and most likely all younger new techs that typically will be doing the PMs. That's what my 24 years field experience tells me any way.

Interesting! I heard about the Greenspeed (and whatever Trane calls theirs)... had not heard much about testing or owning one.

New technology is always expensive and usually has bugs. I say: give it a few years, lets see how they get the bugs out of it.

And I agree; a VS drive furnace with proper AC sizing (and proper duct design) probably will work just as good if not better.

I do hope the technology is developed... as if it is not; multi-head mini's may take a slice from the ducted business.

Two very good counter points that should be considered. Those issues mean net cost analysis, Greenspeed probably will be more. Guess it depends how much heating cost savings there are in that big COP jump.

He'll probably not be putting in one much less two Greenspeeds, but without them in the cost/benefit analysis, the decision matrix is incomplete and biased. Poor or biased perspective leads to bad decisionmaking. If it were my audit I'd be modelling them to understand net cost.

My mother complained of icebox basement as well. We found that if she turns her fan to "On Medium" in April, then back to auto in July it seems to solve her icebox basement problem. I think she subsequently has gone to "On Low" the rest of the year, it keeps parts of the house from getting stale and dramatically cut dusting.

The idea was that by improving air circulation/mixing through the house during the period equipment otherwise seldom runs, and that the ground is coldest (pulling a lot of BTU from the basement that aren't being replaced), it evens temperatures throughout and you actually gain some cooling benefit to the rest of the house from the cold mass.

This assumes you have a low return in the basement, you want return pulling from the coldest location (hopefully Brian won't see this).

Been telling folks this for years (hilited and underlined part)...

As soon as that little amount of moisture from the coil is gone... the circulation helps the rest of the house until the next cool call. In heat season, it is all good!

Have a customer that is looking at a MOD furnace with 2 stage AC... should be an interesting system. I plan to use the HoneyWell Presitge IAQ with remote... customer likes the idea of T-stat being mobile. If they buy it, will post some details.

As soon as that little amount of moisture from the coil is gone... the circulation helps the rest of the house until the next cool call. In heat season, it is all good!

Infinity manages humidity too, including dropping to low stage if sensible is dropping faster than latent and driving below set point in an attempt to drop rh. At end of cycle it will stop the fan, I think for 5 minutes, to allow the coil to drain.

Infinity manages humidity too, including dropping to low stage if sensible is dropping faster than latent and driving below set point in an attempt to drop rh. At end of cycle it will stop the fan, I think for 5 minutes, to allow the coil to drain.

The fan off delay is selectable in the curent version of the controller up to I think 60 minutes. I think I set mine to 60.

Another thing to consider is that here in central florida we are part of Hurricane Alley, with that we are having a generator installed that will power most of the systems in the house. If we go with split systems we can get a smaller generator and only need to power the downstairs of the house in the event of an outage.

Infinity manages humidity too, including dropping to low stage if sensible is dropping faster than latent and driving below set point in an attempt to drop rh. At end of cycle it will stop the fan, I think for 5 minutes, to allow the coil to drain.

I appreciate the hope that the sales claims of newly developed a/c designs are going to solve the humidity control problem that we have. These new a/cs are better than the old single speed a/c but they have limitations.
A very small amount of the moisture on a coil drain at the end of the cooling cycle. High seer coils hold about 1 lb. per ton at the end of the cooling cycle. Only a couple onces drains in several minutes at the end of the cycle. The rest evaporates back into the house. If the fan is on low, the coil dries in about one hour. If the fan is off, it takes about two hours for the coil to dry back to the home. Yes, the VS a/cs slow the cooling rate if the %RH is above the setting. But during low/no cooling loads, there is not enough sensible cooling to remove the latent load that is typical in occupied homes with minimal infiltration.
I suggest that you get humidity control assurance in writing. There are many months of latent cooling loads without significant sensible cooling. Adding a small whole house dehumdifier makes maintaining <50%RH with out any sensible cooling load easy. Also these dehus have the capability of providing fresh air when the home is occupied and the wind is calm. Imagine <50%RH without any cooling.
This was more of draught year, while many years we get months of wet cool weather in any green grass climate.
Regards TB

Cant seem to find any local dealer info on the Ultra-Aire website. Any help?

Your a/c contractor is the right person for this job. We will provide the technical info for a ideal install. Ultra-Aire is available at local wholesalers. Have your a/c contractor call in for info. It is simple install. Thanks for your support.
Regards TB

First, I want to thank everyone for their advice, comments and insight.

Next, and I think I know the answer to this, it seems to me that everyone recommends going with the contrator who is the most knowlegable, professional and I beleive is going to do the best install, despite what brands they recommend. Before I started all this, I was leaning towards Trane, but the contractor who recommended Carrier (does not install Trane), seems like the best group for the job.

Finally, at least for this question, what is the cost/benefit with going with 2 two stage systems, vs. a two stage system for upstairs and one stage for downstairs or for that matter the other way around?

Originally Posted by teddy bear

Your a/c contractor is the right person for this job. We will provide the technical info for a ideal install. Ultra-Aire is available at local wholesalers. Have your a/c contractor call in for info. It is simple install. Thanks for your support.
Regards TB

Another thing to consider is that here in central florida we are part of Hurricane Alley, with that we are having a generator installed that will power most of the systems in the house. If we go with split systems we can get a smaller generator and only need to power the downstairs of the house in the event of an outage.

This just adds to the decision between one and 2 systems.

Some of the generators (installed models) have a power management option; it manages the load so you do not need as large a generator, yet can still have the necessary things work.

It seems to me that everyone recommends going with the contrator who is the most knowlegable, professional and I beleive is going to do the best install, despite what brands they recommend. Before I started all this, I was leaning towards Trane, but the contractor who recommended Carrier (does not install Trane), seems like the best group for the job.

What is the cost/benefit with going with 2 two stage systems, vs. a two stage system for upstairs and one stage for downstairs or for that matter the other way around?